Bevan Frizzell

Reliability and predictability of the centre-edge angle in the assessment of pincer femoroacetabular impingement.

PurposeThe aim of the study was to assess the use of the centre-edge (CE) angle in the assessment of pincer femoro-acetabular impingement (FAI) for reliability and predictability in the diagnosis.MethodsBetween 2004 and 2008, 55 patients underwent surgical treatment for FAI. A control group of 30 was identified among patients attending the emergency department with normal radiographs. Radiographs were assessed by two independent observers both before and after the operation. Nine patients with trauma were excluded. The magnetic resonance arthrogram reports of the remaining 46 patients were assessed for pincer FAI. Nineteen patients were identified and underwent repeat radiographic assessment. All underwent surgical dislocation of hip (SDH), acetabular, with/without femoral osteochondroplasty. Acetabular depth and version were also assessed. The intraclass correlation (ICC) was used to assess reliability of the CE angle. The paired t test and independent groups t test were used to assess the difference between the pincer FAI group, both pre-op and post-op and against controls.ResultsThe control and pincer groups were similar in demographics (p=0.1769). Coxa profunda was present in 14 patients with eight also having retroverted acetabuli. Of the rest two had retroverted acetabuli and one protrusio. The mean CE angle in the control group was 31.4°, in the pre-op pincer group 46.2° and in the post-op pincer group 38.3°. The ICC for intra-observer correlation was 0.977 and 0.992 pre-op and 0.986 and 0.974 post-op. The ICC for inter-observer correlation was 0.960 and 0.957 pre-op and 0.979 and 0.967 post-op.The p value was <0.001 between the controls, the pre-op and post-op pincer groups. The test characteristics using the CE angle ≥ 40 is a reasonably good predictor of FAI, with a sensitivity of 84.2% and a specificity of 100%.ConclusionsThe pincer FAI can be reliably assessed with the CE angle and can be predicted in patients presenting with FAI.

Minimizing the source of nociception and its concurrent effect on sensory hypersensitivity: an exploratory study in chronic whiplash patients.

BackgroundThe cervical zygapophyseal joints may be a primary source of pain in up to 60% of individuals with chronic whiplash associated disorders (WAD) and may be a contributing factor for peripheral and centrally mediated pain (sensory hypersensitivity). Sensory hypersensitivity has been associated with a poor prognosis. The purpose of the study was to determine if there is a change in measures indicative of sensory hypersensitivity in patients with chronic WAD grade II following a medial branch block (MBB) procedure in the cervical spine.MethodsMeasures of sensory hypersensitivity were taken via quantitative sensory testing (QST) consisting of pressure pain thresholds (PPTs) and cold pain thresholds (CPTs). In patients with chronic WAD (n = 18), the measures were taken at three sites bilaterally, pre- and post- MBB. Reduced pain thresholds at remote sites have been considered an indicator of central hypersensitivity. A healthy age and gender matched comparison group (n = 18) was measured at baseline. An independent t-test was applied to determine if there were any significant differences between the WAD and normative comparison groups at baseline with respect to cold pain and pressure pain thresholds. A dependent t-test was used to determine whether there were any significant differences between the pre and post intervention cold pain and pressure pain thresholds in the patients with chronic WAD.ResultsAt baseline, PPTs were decreased at all three sites in the WAD group (p < 0.001). Cold pain thresholds were increased in the cervical spine in the WAD group (p < 0.001). Post-MBB, the WAD group showed significant increases in PPTs at all sites (p < 0.05), and significant decreases in CPTs at the cervical spine (p < 0.001).ConclusionsThe patients with chronic WAD showed evidence of widespread sensory hypersensitivity to mechanical and thermal stimuli. The WAD group revealed decreased sensory hypersensitivity following a decrease in their primary source of pain stemming from the cervical zygapophyseal joints.

Cervical Radiofrequency Neurotomy Reduces Central Hyperexcitability and Improves Neck Movement in Individuals with Chronic Whiplash

OBJECTIVE This study aims to determine if cervical medial branch radiofrequency neurotomy reduces psychophysical indicators of augmented central pain processing and improves motor function in individuals with chronic whiplash symptoms. DESIGN Prospective observational study of consecutive patients with healthy control comparison. SETTING Tertiary spinal intervention centre in Calgary, Alberta, Canada. SUBJECTS Fifty-three individuals with chronic whiplash associated disorder symptoms (Grade 2); 30 healthy controls. METHODS Measures were made at four time points: two prior to radiofrequency neurotomy, and 1- and 3-months post-radiofrequency neurotomy. Measures included: comprehensive quantitative sensory testing (including brachial plexus provocation test), nociceptive flexion reflex, and motor function (cervical range of movement, superficial neck flexor activity during the craniocervical flexion test). Self-report pain and disability measures were also collected. One-way repeated measures analysis of variance and Friedmans tests were performed to investigate the effect of time on the earlier measures. Differences between the whiplash and healthy control groups were investigated with two-tailed independent samples t-test or Mann-Whitney tests. RESULTS Following cervical radiofrequency neurotomy, there were significant early (within 1 month) and sustained (3 months) improvements in pain, disability, local and widespread hyperalgesia to pressure and thermal stimuli, nociceptive flexor reflex threshold, and brachial plexus provocation test responses as well as increased neck range of motion (all P < 0.0001). A nonsignificant trend for reduced muscle activity with the craniocervical flexion test (P > 0.13) was measured. CONCLUSIONS Attenuation of psychophysical measures of augmented central pain processing and improved cervical movement imply that these processes are maintained by peripheral nociceptive input.

A comparison of physical and psychological features of responders and non-responders to cervical facet blocks in chronic whiplash

BackgroundCervical facet block (FB) procedures are often used as a diagnostic precursor to radiofrequency neurotomies (RFN) in the management of chronic whiplash associated disorders (WAD). Some individuals will respond to the FB procedures and others will not respond. Such responders and non-responders provided a sample of convenience to question whether there were differences in their physical and psychological features. This information may inform future predictive studies and ultimately the clinical selection of patients for FB procedures.MethodsThis cross-sectional study involved 58 individuals with chronic WAD who responded to cervical FB procedures (WAD_R); 32 who did not respond (WAD_NR) and 30 Healthy Controls (HC)s. Measures included: quantitative sensory tests (pressure; thermal pain thresholds; brachial plexus provocation test); nociceptive flexion reflex (NFR); motor function (cervical range of movement (ROM); activity of the superficial neck flexors during the cranio-cervical flexion test (CCFT). Self-reported measures were gained from the following questionnaires: neuropathic pain (s-LANSS); psychological distress (General Health Questionnaire-28), post-traumatic stress (PDS) and pain catastrophization (PCS). Individuals with chronic whiplash attended the laboratory once the effects of the blocks had abated and symptoms had returned.ResultsFollowing FB procedures, both WAD groups demonstrated generalized hypersensitivity to all sensory tests, decreased neck ROM and increased superficial muscle activity with the CCFT compared to controls (p < 0.05). There were no significant differences between WAD groups (all p > 0.05). Both WAD groups demonstrated psychological distress (GHQ-28; p < 0.05), moderate post-traumatic stress symptoms and pain catastrophization. The WAD_NR group also demonstrated increased medication intake and elevated PCS scores compared to the WAD_R group (p < 0.05).ConclusionsChronic WAD responders and non-responders to FB procedures demonstrate a similar presentation of sensory disturbance, motor dysfunction and psychological distress. Higher levels of pain catastrophization and greater medication intake were the only factors found to differentiate these groups.

Derivation of a clinical decision guide in the diagnosis of cervical facet joint pain

OBJECTIVE To derive a clinical decision guide (CDG) to identify patients best suited for cervical diagnostic facet joint blocks. DESIGN Prospective cohort study. SETTING Pain management center. PARTICIPANTS Consecutive patients with neck pain (N=125) referred to an interventional pain management center were approached to participate. INTERVENTIONS Subjects underwent a standardized testing protocol, performed by a physiotherapist, prior to receiving diagnostic facet joint blocks. All subjects received the reference standard diagnostic facet joint block protocol, namely controlled medial branch blocks (MBBs). The physicians performing the MBBs were blinded to the local anesthetic used and findings of the clinical tests. MAIN OUTCOME MEASURES Multivariate regression analyses were performed in the derivation of the CDGs. Sensitivity, specificity, positive and negative likelihood ratios, and 95% confidence intervals (CIs) were calculated for the index tests and CDGs. RESULTS A CDG involving the findings of the manual spinal examination (MSE), palpation for segmental tenderness (PST), and extension-rotation (ER) test demonstrated a specificity of 84% (95% CI, 77-90) and a positive likelihood ratio of 4.94 (95% CI, 2.8-8.2). Sensitivity of the PST and MSE were 94% (95% CI, 90-98) and 92% (95% CI, 88-97), respectively. Negative findings on the PST were associated with a negative likelihood ratio of .08 (95% CI, .03-.24). CONCLUSIONS MSE, PST, and ER may be useful tests in identifying patients suitable for diagnostic facet joint blocks. Further research is needed to validate the CDGs prior to their routine use in clinical practice.

Modulation of Cervical Facet Joint Nociception and Pain Attenuates Physical and Psychological Features of Chronic Whiplash: A Prospective Study

To investigate changes in clinical (physical and psychological) features of individuals with chronic whiplash−associated disorder who had previously undergone cervical radiofrequency neurotomy at the time point when the effects of radiofrequency neurotomy had dissipated and pain returned.

Low Pain Catastrophization and Disability Predict Successful Outcome to Radiofrequency Neurotomy in Individuals with Chronic Whiplash

Physical and psychological symptoms of individuals with chronic whiplash‐associated disorders (WAD) are modulated by successful treatment with cervical radiofrequency neurotomy (cRFN). However, not all individuals respond to cRFN, and it is unknown which clinical features predict successful response to cRFN.

The effect of prolotherapy on sacro-iliac joint stiffness: a pilot study

Abstract The aim of this pilot study was to measure stiffness of the sacro-iliac joints (SIJ) using Doppler imaging of vibration (DIV) before and after prolotherapy injections. Ten subjects, who were already scheduled for prolotherapy injections to their posterior pelvic girdle, were assessed by DIV, a visual analog scale (VAS) and a Roland Morris Back Disability (RMQ) Questionnaire on two occasions before prolotherapy and once 3 months after prolotherapy injections. Vibrations were applied independently to both anterior superior iliac spines of prone subjects. The vibrations were recorded by a color Doppler imaging transducer placed over the ipsilateral SIJ. The intensity of the vibrations on the sacrum and the ilium was measured in threshold units. The differences between the threshold scores were interpreted as the power loss of vibrations through the SIJ. A paired samples t-test was used to analyze the pain and disability data while the DIV data were analyzed with a Wilcoxon Rank Sign test; statistical significance was set at P = 0.05 for all analyses. There was a significant pre- to post-intervention difference for pain (P = 0.001) and disability scores (P = 0.022) after prolotherapy. There was no statistically significant pre to post-intervention difference in the stiffness of the SIJ as measured by DIV (P = 0.14). Subjects that were thought to have pain arising from SIJ laxity showed improved scores for pain and disability after prolotherapy injections, but this study failed to show a difference in SIJ stiffness as measured by DIV. Other mechanisms for the reduced pain and improved function may need to be considered.